• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.247.1-247.1
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• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.130-137
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• 2013

This paper presents analog front-end(AFE) circuits for bio-potential measurement. The proposed AFE is composed of IA(instrument amplifier), BPF(band-pass filter), VGA(variable gain amplifier) and SAR(successive approximation register) type ADC. The low gm(LGM) circuits with current division technique and Miller capacitance with high gain amplifier enable IA to implement on-chip AC-coupling without external passive components. Spilt capacitor array with capacitor division technique and asynchronous control make the 12-b ADC with low power consumption and small die area. The total current consumption of proposed AFE is 6.3uA at 1.8V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.55-64
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• 2007

This paper represents characteristics and design example of series loaded LCC type high frequency resonant DC-DC converter with variable parallel capacitor in the secondary side of inductive power transformer. In this converter, ZVS(zero voltage switching) technique is applied to reduce turn-off switching losses, and the applied converter used the PFM switching pattern to control output voltage. The operating characteristics of the proposed converter is analyzed using nomalized parameter such as switching frequency and load factor with varing the secondary parallel resonant capacitor. The results of analysis show the operating characteristics and design method of the proposed converter using characteristic values. And the proposed converter can be applied for the contactless power supply with linear transfer system such as dean room facilities of semiconductor and Flat Panel Display.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1868-1870
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• 2000

As a drive for an ETC (Electro-thermal Chemical) launcher, a large pulse power system of a 2.4MJ energy storage was designed, constructed and tested. The overall power system consists of eight capacitive 300kJ energy storage banks. In this paper we describe the design features, setup and operation test result of the 300kJ pulsed power module. Each capacitor bank of the 300kJ module consists of six 22kV 50kJ capacitors. A triggered vacuum switch (TVS-43) was adopted as the main pulse switch. Crowbar diode circuits, variable multi-tap inductors and energy dumping systems are connected to each high power capacitor bank via bus-bars and coaxial cables. A parallel crowbar diode stack is fabricated in coaxial structure with two series 13.5kV, 60kA avalanche diodes. The main design parameters of the 300kJ module are a maximum current of 180kA and a pulse width of 0.5 - 3ms. The electrical performances of each component and current output variations into resistive loads have been investigated.

• Journal of IKEEE
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• v.13 no.1
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• pp.41-48
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• 2009

This paper describes an implementation of the analog front end (AFE) incorporated with the image signal processing (ISP) unit in the SoC, dominating the performance of the CCD image sensor system. New schemes are exploited in the high-frequency sampling to reduce the sampling uncertainty apparently as the frequency increases, in the structure for the wide-range variable gain amplifier (VGA) capable of $0{\sim}36\;dB$ exponential gain control to meet the needed bandwidth and accuracy by adopting a new parasitic insensitive capacitor array. Moreover, the double cancellation of the black-level noise was efficiently achieved both in the analog and the digital domain. The proposed topology fabricated in a $0.35-{\mu}m$ CMOS process was proved in a full CCD camera system of 10-bit accuracy, dissipating 80 mA at 15 MHz with a 3.3 V supply voltage.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.8
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• pp.392-398
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• 2006

The properties of tunable dielectric materials on RF frequency band are important high tunability and low loss for RF variable devices, variable capacitor, phased array antenna and other components application. Various composite of BST(barium strontium titanate) ratio combined with other non-electrical active oxide ceramics have been formulated for such uses. We present the tunable properties and Curie temperature on BST thick films. The grain growth of the weight ratio of $BaTiO_3$ increased. This can be explained by the substitute $Sr^{2+}$ ion for $Ba^{2+}$ ion in the $BaTiO_3$ system. The Curie temperature was shifted to lower temperature with increasing $SrTiO_3$in the $BaTiO_3-SrTiO_3$ system, because of decreasing the lattice constant. Also, the dielectric constant, tunability and K-factor of $(Ba_xSr_{1-x})TiO_3$ at over the Curie temperature decreased, at over the $60^{\circ}C$ fixation, maximum dielectric constant at Curie temperature and hence sharper phase transformation occurred at Curie temperature. The result were interpreted as a process of internal stress relaxation resulting form the increase of $90^{\circ}$ domains induced the BST. As a result, It is concluded that over the Curie temperature, frequency response and DC field effect for the tunable properties of BST thick film are suppressed by the transition broadening. For the application of tunable devices, that the curie temperature was investigated to be increased.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.68-74
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• 2010

A sub-${\mu}$W CMOS Wien-Bridge oscillator for ultra low power (ULP) radio applications is presented. The Wien-Bridge oscillator is based on an non-inverting opamp amplifier with a closed-loop gain $1+R_2/R_1$ as a means of providing necessary loop gain. An additional RC network provides appropriate phase shift for satisfying the Barkhausen oscillation condition at the given frequency of 1/($2{\pi}RC$). In this design, we propose a novel loop gain control method based on a variable capacitor network instead of a rather conventional variable resistor network. Implemented in $0.18{\mu}m$ CMOS, the oscillator consumes only 560 nA at the oscillation frequency of 22 kHz.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.11-116
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• 2000

A topology decreased switching loss and voltage stress by zero voltage switching is presented in this paper. Generally, Switching mode converting productes voltage stress and power losses due to excessive voltage and current. which affect to performance of power supply and reduce overall efficiency of equipments. Virtually, In flyback converter, transient peak voltage and current at switcher are generated by parasitic elements. To solve these problems, present ZVS flyback converter topology applied a auxiliary circuit. Incorporation of auxiliary circuit into a conventional flyback topology serves to reduce power losses and to minimize switching voltage stress. Snubber capacitor in auxiliary circuit serves ZVS state by control voltage variable time at turn on and off of main switch, then reduces voltage stress and power losses. The proposed converter has lossless switching in variable load condition with wide range. A detailed analysis of the circuit is presented and the operation procedure is illustrated. A (50W 100kHz prototype) ZVS flyback converter using a auxiliary circuit is built which shows an efficiency improvement as compared to a conventional hard switching flyback converter.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.58-65
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• 2009

In this paper, we designed high voltage gate drive IC including dead time circuit in which capacitors controlled rising time and falling time, and schimitt-triggers controlled switching voltage. Designed High voltage gate drive IC improves an efficiency of half-bridge converter by decreasing dead time variation against temperature and has variable dead time by the capacitor value. and its power dissipation, which is generated on high side part level shifter, has decreased 52 percent by short pulse generation circuit, and UVLO circuit is designed to prevent false-operation. We simulated by using Spectre of Cadence to verify the proposed circuit and fabricated in a 1.0um process.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.98-107
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• 2016

An analytical comparison of a synthetic memristor emulator and a M-R mutator-based memristor emulator has been performed. Memristor is an electrical element with the characteristic of variable resistance. It is called the fourth fundamental electrical element following resistor, capacitor, and inductor. Memristor emulator is a circuit which implements the feature of variable resistance via the composition of various electrical devices. It is an essential circuit to study memristor characteristics during the time before it is commercially available. There are two representative memristor emulators depending upon their implementation methods. One is a memristor emulator which is synthesized via combining various electrical devices and the other one is M-R mutator-based memristor emulator implemented by extracting resistance from a nonlinear device. In this paper, implementation methods of these two memristor emulators are studied and their differences are investigated by analysing their characteristics.